US 2002/0077247 discloses a NOx storage catalyst in honeycomb form, wherein the honeycomb is formed from at least one alkaline earth metal sulphate as precursor compound of a NOx storage material. The catalyst typically contains a transition metal, preferably a metal from the group consisting of palladium, platinum, rhodium, iridium and ruthenium, which metals may be introduced by sol impregnation or by dipping in a salt solution.
Society of Automotive Engineers (SAE) Technical Paper 2007-01-0658 is entitled “Fundamental Study and Possible Application of New Concept Honeycomb Substrate for Emission Control” and discloses a diesel oxidation catalyst (DOC) comprising a platinum catalyst dispersed on a catalytic carrier comprising a plurality of extruded segments of gamma-alumina, inorganic fibres and (unnamed) binding material adhesively combined into a full size block. The platinum is applied to the catalytic carrier by a normal impregnation method at 1.0 to 2.7 g per litre. The paper suggests that a NOx Storage Catalyst (NSC) can also be made in the same way, although no specific example is provided.
EP 1739066 discloses a honeycomb structure comprising multiple honeycomb units having multiple through holes; and a seal layer that joins honeycomb units with each other via respective closed outer faces of the honeycomb units where the through holes are not open. The honeycomb unit includes at least inorganic particles, inorganic fibers and/or whiskers. The inorganic particles exemplified are alumina, titania, silica and zirconia; the inorganic fibres exemplified are silica alumina fibres; and the inorganic binders exemplified are silica sol, alumina sol, sepiolite and attapulgite. A catalyst component can be carried on the honeycomb structure. The catalyst component may include at least one type selected among noble metals including platinum, palladium and rhodium, alkali metals such as potassium and sodium, alkaline earth metal e.g. barium and oxides. The honeycomb structure can be used as a catalytic converter e.g. a three-way catalyst or a NOx storage catalyst for conversion of the exhaust gas of vehicles.
WO 2009/093071 discloses a wall-flow filter monolith substrate having a porosity of at least 40% formed from a selective catalytic reduction catalyst of extruded type.